The instant invention concerns a paper supply device, specifically for use in a cardboard manufacturing production line, said device comprising two parallel winders, one behind the other, each supporting a spool of paper, the first spool being a working spool and the second a reserve spool, said winders being alternately activated to ensure a continuous supply of paper to the production line, said device also comprising a drive means for the feed mechanisms, a means for detecting the end of the strip on the working spool, and a means for automatically attaching the end of the strip on the working spool to the beginning of the strip on the reserve spool.
In the cardboard manufacturing industry such paper supply devices are well known. They usually consist of two winders, each in the form of a support with two arms holding the spool of paper, which is emptied when the production line drive rollers exert a pull on the spool of paper. When the working spool, which is rotating, is joined to the reserve spool, which is stopped, either the production line slows down due to the resistance resulting from the new full spool starting up, or else the roll of paper yields to the pull exerted. This affects both the output of the production line and the quality of cardboard produced.
In order to connect the end of the working spool strip with the beginning of the reserve spool strip, a specific assembly device that is separate from the supply mechanism is usually used, currently known as a xe2x80x9csplicer.xe2x80x9d An operator is required to intervene when the rolls are joined in order to prepare the connection, properly position the beginning of the strip in relation to the end of the strip, and ensure that they are correctly spliced. Thus, splicing cannot take place automatically; an operator is required. The xe2x80x9csplicer,xe2x80x9d usually located overhead, is a heavy, expensive piece of equipment. Furthermore, when either the type of paper or paper width must be changed, manual intervention is required for splicing and repositioning the arms of the winders, etc. Since it is not possible to intervene instantly, the operator is obliged to slow the production line down, decreasing output.
Moreover, in order to remove an empty spool and replace it with a full one, the arms must be lowered, separated, and then closed. This intervention takes five minutes of an operator""s time. Although the spools can be loaded and unloaded automatically, this takes a long time. Furthermore, the empty or full spools are manipulated by conventional trolleys equipped with a means for gripping the spools.
Certain semi-automatic or automatic splicing devices which exist in the art are described in the following publications. In Publication DE-B-12 81 766, the assembly device comprises two parallel loose rollers, arranged between the two spools at the top portion and attached to a support which pivots on the axle of the third loose roller located at the lower portion, placing the first roller in contact with the reserve spool in order to connect the end of the working spool strip with the beginning of the reserve spool strip. The first two rollers are attached to a turning plate which pivots 180xc2x0 and has a handle for manipulation. Thus, the system is very complex, expensive, and does not function entirely automatically, since an operator must intervene to tilt the rollers 180xc2x0 and complete the connection to the other spool.
In publication FR-A-230 571, the assembly device consists of a trolley supporting two diversion rollers, said trolley moving along a ramp above the spools, and said ramp alternately tilting from one spool to the other in order for the strips to be spliced. This device is complex, costly, and clumsy. Furthermore, starting up the winder according to this method is difficult, as it requires that a strip be introduced into the upper diversion rollers.
Finally, in Publication F.R.-A-2 587 982, the splicing device described is for use with superimposed spools. It comprises a movable trolley located beside the spools, holding a support with three diversion rollers between which the strip passes. Once connected, the support pivots about the central roller between two end positions that are angularly offset by approximately 90xc2x0 in order to place one or the other diversion rollers in contact with the waiting spool. Three cylinders are used to pivot said support, one advance cylinder and two contact cylinders. Thus, the device is relatively complex to use, guide, and adjust. The fact that the spools are superimposed complicates the loading and unloading process; these operations are difficult to automate because the manipulations must be performed overhead.
The goal of the present invention is to overcome these disadvantages by proposing a supply device that is simple to use, requires a minimal investment and only a small amount of space, and offers high speed, automatic splicing with no operator intervention, as well as automatic spool loading and unloading. The essential aim of the invention is to significantly reduce the time required to prepare and change spools while at the same time offering a means for splicing the spools at very high speed with no risk to the paper or to the production line.
This goal is achieved by the supply device as described in the preamble, characterized in that the automatic splicing means is located between the two winders, parallel to them, and comprises two diversion rollers that are parallel and separated by a predetermined fixed interval, said diversion rollers extending at least along the entire width of the paper on said spools and receiving the strip of paper corresponding to the working spool, and said two diversion rollers rotating freely on at least one common plate and being driven to rotate on their axles by the strip of paper as it unfurls, while the plate itself rotates at a fixed angle on a trolley so that it alternately places the diversion rollers in a first connected position and then in a second connected position, respectively, corresponding to the working spool, with said trolley moving in translation perpendicular to the axis of the spools so as to place one of the diversion rollers in contact with the working spool in said connected positions. Said splicing device also comprises a means for driving said plate and a means for driving said trolley.
In a preferred form of the invention, the means for driving said plate comprises at least one motor and one mechanical transmission between the drive shaft and the plate to alternately turn the plate at an angle smaller than 360xc2x0, with the limits of this angle corresponding to the two connection positions for said diversion rollers, said angle ranging from 250xc2x0 to 290xc2x0 and preferably being equal to 270xc2x0.
The automatic splicing means may consist of at least two parallel rails attached to the floor perpendicular to said spools with the rails being separated by a distance which is at least equal to the span of the spools, and each rail being equipped with a rack. The trolley may have at least one motorized beam extending between the two rails, equipped at each end with a pinion engaging the rack of the corresponding rail, and the drive means for the movable trolley may comprise at least one motor and one mechanical transmission connected to said motorized beam.
Each winder advantageously comprises at least one chassis attached to the floor, one platform attached to said chassis, and two pairs of drive rollers parallel to the spool axis, said two pairs being aligned and designed to support the roll of paper; the drive means for the winder comprises a motor and a mechanical transmission between the drive shaft and one of the drive rollers, with the other drive rollers being driven by the rotating spool.
In the preferred form of the embodiment, each winder comprises two platforms, each supporting a pair of drive rollers, said two platforms moving in translation symmetrically in relation to the median axle A of said device, said median axle being perpendicular to the axis of the spools, in order to adjust the interval between the two pairs of rollers to the width of said spool.
The chassis of each winder may comprise two sections that are parallel to each other and to the spool axis, at least one section supporting the rack, and the platforms may comprise at least two slides which slide along or inside said sections and at least one motor, which is a stepping motor, driving a pinion that engages said rack.
Advantageously, each winder comprises two turning vertical stops each located between two drive rollers in the same pair, designed to block the spool axially.
In the preferred form of the invention, each winder comprises a counterweight designed to exert a push on each spool toward drive rollers.
Said counterweight comprises, for example, an arm moving in vertical translation along a fixed post between an upper position, corresponding to a full spool, and a lower position, corresponding to an empty spool, as well as a means for automatically raising said arm; and said arm supporting at least two loose pulleys that are parallel to each other and to the spool and designed to contact the spool.
The arm may comprise four pulleys, two exterior loose pulleys designed to contact the spool when it is full and two interior loose pulleys designed to contact the spool when it is empty, and the means for raising the arm may comprise a dual-action cylinder controlled by an electrovalve.
Advantageously, the means for detecting the end of the strip on the working spool consists of at least one detector associated with said counterweight and designed to detect the arm position that corresponds to the minimum working spool diameter which would permit connection of the end of the strip on said spool to the beginning of the strip on the reserve spool.
The means for detecting the end of the strip on the working spool is designed to send one signal to the winder drive means corresponding to the reserve spool, signaling the reserve spool to rotate. The beginning of the strip on this spool has a visual indicator and a cold glue mesh extending over its entire width.
Preferably, the splicing means comprises a presence detector designed to detect the visual indicator located on the rotating reserve spool, said presence detector being designed to send a simultaneous signal to the trolley drive means and to the plate drive means to displace the trolley towards the reserve spool and to move said diversion rollers from the first connection position to the second, and conversely, depending upon which spool is the working spool.
In the preferred embodiment, the automatic splicing means comprises at least one cutting blade generally extending over the entire width of the spools, located essentially below said trolley and movable in vertical translation between a lower waiting position and an upper working position where it cuts the end of the strip on the working spool.
In addition, the device according to the invention advantageously comprises a means for automatically loading and unloading the spools which removes the empty spools and replaces them with full ones.
In accordance with the preferred embodiment, each winder comprises between its two platforms a plate which can move in vertical translation between a lower waiting position and an upper working position, said plate comprising a track consisting of several motorized rollers that are parallel to each other and perpendicular to the spool axis, said rollers being rotated by a motorized device and designed to support and axially displace said spool when the plate is raised in order to position it in the winder if it is a full spool, or to remove it from the winder if it is an empty one.
The plate may have at least two vertical dual-action cylinders to displace it from the lower position to the upper position, and conversely, and the motorized device may comprise at least one motor and one chain and pinion transmission or gear and pulley transmission to simultaneously drive said rollers.